A fast-moving, 170-acre brush fire near Castaic Lake dubbed the Castaic Fire reached 50% containment by Sunday morning, according to Angeles National Forest officials.

Overnight, crews were able to build hand and dozer lines, only allowing the acreage to grow slightly to 178, per ANF officials.

Crews are expected to remain on the scene through the day to continue building containment lines and searching for hotspots, with full containment expected by the end of the day.

Crews first responded to reports of the fire near the lake’s boat launch on the 32000 block of Castaic Lake Drive around 4:04 p.m. Saturday, according to Andrew Mitchell, ANF spokesman.

LACoFD assisting @Angeles_NF w/the #CastaicFire this afternoon.

— LACoFD (@LACOFD) August 2, 2020

With assistance from the Los Angeles County Fire Department, ANF personnel led the assault.

Dubbed the Castaic Fire, the blaze reached 1 acre around 4:20 p.m., and was running uphill in an old burn area from years back with medium to heavy fuel, according to firefighters on the scene.

“We sent a full first alarm brush response,” Mitchell said as the fire had first started spreading. “Usually, we send five engines, but now with high temperatures, we send seven. We also sent out patrols, a tanker, copters and dozers.”

A Los Angeles County Fire Department helicopter aids firefighters as they battle the Castaic Fire near Castaic Lake on Saturday, Aug. 1, 2020. | Photo: Dan Watson / The Signal.

By 5:40 p.m., the Castaic Fire had grown to 160 acres with 0% containment, prompting the closure of the lake and Templin Highway from Ridge Route East, though no structures were reported threatened.

Local firefighters were joined by others who had traveled from Wyoming and Arizona to help bolster the U.S. Forest Service’s capacity in Southern California, per ANF officials.

Firefighters were able to hold the Castaic Fire at 170 acres with 0% containment by 7 p.m., according to Mitchell.

“A rapid and aggressive attack by the Forest Service and Los Angeles County Fire have stopped the forward rate of spread holding the fire at approximately 170 acres,” Incident Commander Oscar Vargas said in a statement.

Signal Staff Writer Tammy Murga contributed to this report.